'Banded' Photo Rendering

[Scott Bulmer]

I am at a loss for what causes (the attached) incomplete photo rendering made up of partial image bands, and am open to any suggestions. The PLN file is approximately 11 MB with the buildings as multi-story modules (5 stories total). The roof utilizes the Italian tile roof surfacer, however that layer is off for these renderings. The Open GL engine works as expected, but Lightworks does not fully render the image (even with low level settings). Light Sources is set to lamps (sun and sky objects that are turned on in the plan window), with shadow casting by lamp settings. Other smaller PLN project files photo render as expected.

[Karl Ottenstein]

Interesting, Scott. There's lots of polygons in them there tiles! (Nice looking model, by the way.)

So, if it never fully displays in OpenGL or wireframe, it does sound like polygon overload. I'll be interested to hear what happens on another computer.

Not being able to view the model in 3D blocks all kinds of other options. For example, Artlantis R deals with large polygon count models very well, by all accounts. While you could download the demo version (30 day trial) to check it out ... you have to export to ATL from the 3D window ... and you can't display in the 3D window...

That you observe what you do (banding) when the roof surfacer layer is turned off makes this more puzzling. I would have thought the all of the tiles were the problem. So, there may be more than one issue going on. Look forward to hearing what happens on a different computer.

(Re: your earlier message, I don't think you have to have a tech remove a processor - not worth the risks of physical removal. If there is not a BIOS setting to logically disable one processor, just continue your tests on a different computer.)

Karl

PS One last idea. I had a problem with a 128 MB graphics card once when I stretched my 3D window to span multiple monitors, or even placed it on my secondary monitor. Have you gotten the same results (not able to display in OpenGL) if you place the 3D window on the primary monitor only, and reduced in size to be maybe 800 x 600 pixels worth of whatever your total screen space is?

[Scott Bulmer]

Karl,
Thanks, alot of blood, sweat & tears have gone into that project (no growth California policies).

On a Pent 4 – 253GHz – 1MB ram, Lightworks engine rendered the image with roof surfacer layer off as expected without banding. So that isolates the Dual Xeon having some issue.

On the Pent 4 with roof surfacer on, Shaded Open GL engine rendered the image (no crash as on Dual) in a little more that 3 hours. THEN commenced the LW Photo Rendering process, waited 4 hours finally going to bed. The image was unable to render with the attached error message. You are correct; there must be too many roof tile polygons in the 3-building model.

There appears to be some exponential relationship of rendering time with roof tile surface area; each building alone will render with Open GL in approx. 5 minutes, then an additional 5 minutes in Lightworks (one would estimate 30 minutes total if 3 equal buildings). Attempting to render all 3 equal size buildings at once takes hours with Open GL, and then cannot be completed in LW.

I still haven’t any ideas on the banding issue other than it’s isolated to the Dual Xeon. AFA bios settings, I am willing to try but am not terribly experienced with system settings.

To complete this project I will try to render each building alone, then reassemble in Photoshop, or will isolate & turn off distant roof tile surfaces.
Thanks again for your thoughtful comments.
Scott

[Anonymous]

Karl wrote:
Interesting, Scott. There's lots of polygons in them there tiles! ...

Not being able to view the model in 3D blocks all kinds of other options. For example, Artlantis R deals with large polygon count models very well, by all accounts. While you could download the demo version (30 day trial) to check it out ... you have to export to ATL from the 3D window ... and you can't display in the 3D window...

You used to be able to set up a camera view looking away from the model and then export that empty view to Artlantis. I assume that this is still possible with Artlantis R.

[Karl Ottenstein]

Millard wrote:
You used to be able to set up a camera view looking away from the model and then export that empty view to Artlantis. I assume that this is still possible with Artlantis R.

Thanks for the reminder, Millard! I'm always forgetting that old trick! A friend sent me this quote this morning, which seems remarkably appropriate: "Right now I'm having amnesia and deja-vu at the same time. I think I've forgotten this before." -- Steven Wright

Scott: Do you have shadow casting turned off for the tile objects? Should help some. (If you are using the SkyObject and SunObject with multiple light sources, the total shadow computation would be enormous if the tiles are casting shadows.) And, of course, the obvious as a workaround: are the tiles really necessary at the zoom/scale of the final image? Would a bump mapped tile image work just as well at your output scale?

Karl

[Dwight]

I have done renderings with buzzillions of Onyx Tree leaves and no trouble.

My suspicion is that there is a problem with the machine or the RAM.

[Scott Bulmer]

To summarize:
1) LW Banding is isolated to Dual Xeon. DX performs normal for all other tasks. Recommendation: Run some form of further diagnostics to be determined.
2) LW will not render excessive Roof Surfacer Italian tiles on either machine. Too many polygons. Recommendation: Punt!
3) Shadow casting was off for all Italian tiles, 3D was set to simple. Lighting sources are sun & sky objects w/ shadow casting by lamp setting.
4) For LW, Karl’s recommendation to change to bump mapped tiles for the distant buildings and Roof Surfacer on for the closest building to the camera. Will try.
5) For Artlantis, Millard’s/Karl’s recommendation to download trial version & export empty view of model (in theory the Open GL shaded view should render much faster looking away from the model, and Artlantis allegedly can handle more polygons than LW).
Thank you all again for your valuable time and insights.
Scott

[Dwight]

how many light sources in your sunandskyobjects?

did you reduce them?

[Scott Bulmer]

Dwight wrote:

how many light sources in your sunandskyobjects?

Interesting question:
15 in the sun, 46 is greyed out in sky with 5 latitude, 15 longitude, shadow quality is 5 and soft (but shadow casting setting for tiles is off).
I haven't tried a reduction of light sources as yet. Could you please recommend a realistic setting at your convenience?

[Dwight]

4-6 suns - for soft light 45 divergence

lat 3 long 6 on the skyobject


what you using?


or give up and use the built-in sun with weak intensity and lots of ambient

[Scott Bulmer]

Dwight wrote:
give up and use the built-in sun with weak intensity and lots of ambient

Per your suggestion above, LW is able to render on the Dual Xeon (see attached). However, it still produces a banding pattern when the sun/sky objects are used, even when reducing the light sources as recommended. This Dual Xeon does not like this model when rendering in LW using the sun/sky objects.